Passage selected from a book (7)
I believe the answer is:
excerpt
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">passage selected from a book</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for excerpt that I've seen before include "Sample of work" , "Passage from literature or music" , "Just a few words" , "Short extract" , "part of article, perhaps" .)